U.S. patent application number 10/198967 was filed with the patent office on 2003-01-30 for elastic-bodied crawler.
Invention is credited to Hori, Kazutoshi.
Application Number | 20030019133 10/198967 |
Document ID | / |
Family ID | 19055898 |
Filed Date | 2003-01-30 |
United States Patent
Application |
20030019133 |
Kind Code |
A1 |
Hori, Kazutoshi |
January 30, 2003 |
Elastic-bodied crawler
Abstract
An elastic-bodied crawler, in which a ground pressure
distribution is equalized and generation of local wear in use is
prevented to provide for durability, and which is driven by drive
power from driven projections provided on an inner peripheral
surface of the crawler, comprises load propagating means embedded
centrally of the crawler in a widthwise direction to extend over
treads of rollers. The load propagating means causes pressing
forces (ground pressure) of the rollers to act generally in the
widthwise direction whereby a ground pressure distribution on a
ground surface of the crawler is equalized, local wear in lug
portions is eliminated to enhance durability of the crawler.
Inventors: |
Hori, Kazutoshi;
(Komatsu-City, JP) |
Correspondence
Address: |
VARNDELL & VARNDELL, PLLC
106-A S. COLUMBUS ST.
ALEXANDRIA
VA
22314
US
|
Family ID: |
19055898 |
Appl. No.: |
10/198967 |
Filed: |
July 22, 2002 |
Current U.S.
Class: |
37/466 |
Current CPC
Class: |
B62D 55/244 20130101;
E02F 9/02 20130101 |
Class at
Publication: |
37/466 |
International
Class: |
E02F 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 24, 2001 |
JP |
2001-222418 |
Claims
What is claimed is:
1. An elastic-bodied crawler driven by drive power from driven
projections provided on an inner peripheral surface thereof,
comprising load propagating means embedded centrally of the crawler
in a widthwise direction to extend in projected areas of treads of
rollers.
2. The elastic-bodied crawler according to claim 1, wherein the
load propagating means is arranged on a side of a reinforcement
layer of main cables embedded in a body toward a portion formed
with lugs.
3. The elastic-bodied crawler according to claim 1, wherein the
load propagating means is formed by arranging and embedding a
multiplicity of cables perpendicularly to a circumferential
direction of the body or on the bias thereto.
4. The elastic-bodied crawler according to claim 2, wherein the
load propagating means is formed by arranging and embedding a
multiplicity of cables perpendicularly to a circumferential
direction of the body or on the bias thereto.
5. The elastic-bodied crawler according to claim 1, wherein the
load propagating means is formed by embedding core bodies having a
higher Young's modulus than that of an elastic material, which
forms the body.
6. The elastic-bodied crawler according to claim 2, wherein the
load propagating means is formed by embedding core bodies having a
higher Young's modulus than that of an elastic material, which
forms the body.
7. The elastic-bodied crawler according to claim 5, wherein a
circumferential pitch of the core bodies in the body is 1/n (n:
integer) times a pitch, in which the driven projections are
provided.
8. The elastic-bodied crawler according to claim 6, wherein a
circumferential pitch of the core bodies in the body is 1/n (n:
integer) times a pitch, in which the driven projections are
provided.
Description
BACKGROUND OF THE INVENTION
[0001] The invention mainly relates to an elastic-bodied crawler
used for construction machines, such as crawler dump truck,
hydraulic excavator and the like, and farm machines.
[0002] Conventionally, an endless elastic-bodied crawler formed by
covering a plurality of metal core members with an organic elastic
material (for example, rubber) has been frequently used in crawler
vehicles such as construction machines and farm machines. However,
there is caused a problem that because of having metal core
members, such elastic-bodied crawler is difficult to cut upon
disposal after use, and so must be discarded as it is, which makes
it difficult to dispose of the crawler as industrial waste. For
such reasons, in recent years, an elastic-bodied crawler without
metal core members has been adopted to facilitate cutting and
disposal at the time of disposal. FIG. 7(a) is a top plan view
showing a concrete example of a conventional elastic-bodied crawler
without metal core members and FIG. 7(b) is a cross sectional view
taken along the line a-a. The conventional elastic-bodied crawler
100 without metal core members is formed integral as shown in FIGS.
7(a) and 7(b) to comprise driven projections 105, which are
provided circumferentially at a predetermined pitch along a center
line on an upper surface, and lug portions 102 having a lug 103
formed on an outer surface side (outer peripheral ground surface
side) of an endless body 101 having a predetermined width and a
predetermined thickness. The body 101 is structurally reinforced by
arranging a multiplicity of reinforcement cables 106 near an inner
surface of the body over an entire width of the body except ear
portions 104 on both sides of the body and over an entire
circumference of the body.
[0003] The elastic-bodied crawler 100 thus structured is wound
round a sprocket and an idler in a traveling section of a crawler
vehicle (not shown) to be able to transmit power in a state, in
which the driven projections 105 provided on an inner surface of
the elastic-bodied crawler 100 at a predetermined pitch engage with
engaging teeth provided on a circumferential surface of the
sprocket, and a multiplicity of rollers provided between the
sprocket and the idler hold a ground surface side of the
elastic-bodied crawler 100 from above to be able to ensure a ground
force. In addition, the elastic-bodied crawler 100 is so structured
that outer peripheral surfaces of the sprocket and the idler bear
flat surfaces 107, 107 on both sides of the driven projections
105.
[0004] Also, with the elastic-bodied crawler 100, reaction forces
during traveling are born by the plurality of rollers 110 provided
for the purpose of ensuring a ground force during traveling and the
flat surfaces 107, 107 on the both sides of the driven projections
105 provided along a center line on an inner surface of the body,
as shown in FIG. 8. In addition, the rollers 110 are mounted on
both side portions of a support shaft 112, an intermediate portion
of which is rotatably born by a bearing 115 provided and supported
on a traveling body frame (not shown), and provided in a manner to
contact on both sides thereof with the flat surfaces 107, 107 and
to bridge areas where the driven projections 105 are provided.
[0005] As described above, with the elastic-bodied crawler 100
wound round the traveling body, load from the rollers 110 is
transmitted to a road surface immediately there below as it is. At
this time, a ground pressure distribution is localized
corresponding to projected surfaces of contact portions of the
rollers 110, 110, as shown in FIG. 8. As a result, the lug portions
102 on the elastic-bodied crawler 100 undergo local wear, as shown
in FIG. 8. When such local wear is generated, there is caused a
problem that not only outward appearance is markedly damaged but
also the elastic-bodied crawler is consequently shortened in
service life because durability of the elastic-bodied crawler 100
is determined by those portions thereof, which are worn
violently.
[0006] In this manner, the elastic-bodied crawler without metal
core members involves a problem that the ground pressure
distribution is inevitably localized because surfaces pressed by
rollers for ensuring pressing forces toward the ground side in
order to ensure ground pressure at the time of running drive are
defined by flat surfaces on both sides bridging the positions of
the driven projections by virtue of the structure, in which driven
projections adapted to engage with the sprocket are formed in a
central portion in a widthwise direction, and the crawler is formed
by an elastic material (for example, rubber), which constitutes the
crawler, and the reinforcement cables arranged
circumferentially.
[0007] The invention has been thought of in order to solve such
problems, and has its object to provide an elastic-bodied crawler,
by which the ground pressure distribution is equalized and in which
generation of local wear in use is prevented to provide for
durability.
SUMMARY OF THE INVENTION
[0008] To attain the above object, the invention provides an
elastic-bodied crawler driven by drive power from driven
projections provided on an inner peripheral surface thereof,
comprising load propagating means embedded centrally of the crawler
in a widthwise direction to extend in projected areas of treads of
rollers.
[0009] According to the invention, since in addition to the
reinforcement cables embedded in the body of the elastic-bodied
crawler in a widthwise direction, the load propagating means is
arranged centrally of the crawler in a widthwise direction to
extend in projected areas of treads of rollers to produce a
difference in rigidity of the elastic-bodied crawler between
portions corresponding to treads of the rollers and the central
portion thereof, pressing forces (ground pressure) of the rollers
applied with portions, on which the driven projections are
provided, therebetween make use of the difference in rigidity to
act uniformly generally in the widthwise direction. As a result,
there is given an effect that a ground pressure distribution on the
ground surface of the crawler is equalized to eliminate local wear
in the lug portions, and friction is equalized to enable enhancing
durability of the crawler.
[0010] The load propagating means is preferably arranged on a side
of a reinforcement layer of main cables embedded in a body toward a
portion formed with lugs (second invention). With such arrangement,
the load propagating means as well as the reinforcement layer of
main cables arranged in the body causes pressing forces applied by
the rollers to be positively transmitted to flat portions, which
bridge portions below and on both sides of the driven projections,
that is, between right and left treads of the rollers in a
widthwise direction, so that ground pressure is distributed over
the central portion, on which load is not directly applied.
[0011] The load propagating means is preferably formed by arranging
and embedding a multiplicity of cables perpendicularly to a
circumferential direction of the body or on the bias thereto (third
invention). With such arrangement, load can be dispersed in a
widthwise direction to act on the ground surface widely. Also, the
load propagating means is preferably formed by embedding core
bodies having a higher Young's modulus than that of an elastic
material, which forms the body (fourth invention). With such
arrangement, pressing forces applied on both sides of the driven
projections by the rollers are transmitted generally in a widthwise
direction by the core members, so that a ground pressure
distribution is equalized to thereby enable preventing local wear
of the crawler ground surface portion. In addition, it is
preferable that the core bodies be formed from a material having a
tensile strength and toughness. Used for the core bodies are
high-hardness rubber, urethane resin, plastics (for example, phenol
resin reinforced by a reinforcement material) having a high
mechanical strength, aluminum, iron or the like.
[0012] A circumferential pitch of the core bodies in the body is
preferably 1/n (n: integer) times a pitch, in which the driven
projections are provided (fifth invention). With such arrangement,
the use of moldings for the core bodies provides an effect that
determination of arrangement and positioning is facilitated, the
function of maintaining a ground pressure distribution uniform
after forming can be fulfilled, and the crawler can be easily cut
at the time of disposal after use.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a view showing a hydraulic excavator with
elastic-bodied crawlers, according to the invention, wound round a
lower running body;
[0014] FIG. 2 is a transverse cross section showing the
elastic-bodied crawler according to a first embodiment;
[0015] FIG. 3 is a view showing the relationship between the
elastic-bodied crawler and rollers;
[0016] FIG. 4 is a transverse cross section showing an
elastic-bodied crawler according to a second embodiment;
[0017] FIG. 5(a) is a transverse cross sectional view showing an
elastic-bodied crawler according to a third embodiment;
[0018] FIG. 5(b) is a longitudinal cross sectional view showing the
elastic-bodied crawler of FIG. 5(a) partially;
[0019] FIG. 6(a) is a transverse cross sectional view showing the
elastic-bodied crawler of the third embodiment provided with
additional means;
[0020] FIG. 6(b) is a transverse cross sectional view showing a
modification of the elastic-bodied crawler of FIG. 6(a);
[0021] FIG. 7(a) is a top plan view showing a concrete example of a
conventional elastic-bodied crawler without core metal members;
[0022] FIG. 7(b) is a cross sectional view taken along the line a-a
in FIG. 7(a); and
[0023] FIG. 8 is a view illustrating ground pressure distribution
on portions of a conventional elastic-bodied crawler, which are
pressed by rollers and a state, in which the elastic-bodied crawler
is worn.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] An explanation will be given below to concrete embodiments
of an elastic-bodied crawler according to the invention with
reference to the drawings.
[0025] FIG. 1 is a view showing a hydraulic excavator with
elastic-bodied crawlers according to the invention, wound round a
lower running body, and FIG. 2 shows a cross section of an
elastic-bodied crawler according to a first embodiment. FIG. 3 is a
view illustrating the relationship between the elastic-bodied
crawler and rollers.
[0026] An elastic-bodied crawler 10 according to the embodiment is
wound round a sprocket 4 and an idler 5, as shown in FIG. 1, which
are arranged on front and rear ends of a track frame 3 on a lower
running body 2 of a crawler vehicle, for example, a hydraulic
excavator 1, and driven by engaging driven projections, which are
provided in a predetermined pitch on an inner peripheral surface
thereof, with drive teeth provided on the sprocket 4. At the time
of driving, a plurality of rollers 6 supported by shafts, which are
rotatably born by bearings of brackets mounted on the track frame
3, push the inner peripheral surface of the crawler to press the
lug portions on the crawler against the ground surface. In
addition, the reference numeral 7 denotes an upper revolving body,
and 8 a working implement provided with a bucket.
[0027] The elastic-bodied crawler 10 according to the first
embodiment comprises, likewise the prior art with respect to an
external appearance, driven projections 13 provided in a
predetermined pitch on an inner peripheral surface 11a of an
endless body 11, which is formed from an elastic material (for
example, rubber) to have a predetermined dimension, and lug
portions 12 provided on an outer peripheral surface of the body to
form a lug of a predetermined shape. As shown in FIG. 2, a
multiplicity of reinforcement cables (main cables 15 (steel cables
or cables of resin fiber)) are arranged and embedded
circumferentially in positions near the inner peripheral surface
11a of the body 11.
[0028] Load propagating means 20 is provided in the body 11 to be
disposed centrally in a widthwise direction and on a side of a
reinforcement layer 15A of the main cables 15 toward the ground
side (side of the lug portions 12).
[0029] The load propagating means 20 is provided in the body 11 to
be disposed on a side of a reinforcement layer 15A of the main
cables 15 toward the ground side and comprises a reinforcement
cable layer 21 comprised of a multiplicity of, for example, steel
cables having a smaller dimension b than a widthwise dimension B of
the body 11 and aligned in a row perpendicularly to a
circumferential direction of the body 11 as shown in FIG. 2, the
reinforcement cable layer bridging root portions of the driven
projections 13 to extend on both sides thereof in a widthwise
direction. In addition, the embodiment comprises, in addition to
the reinforcement cable layer 21 arranged as the load propagating
means 20, an auxiliary cable layer 22 having a smaller dimension
than that of the reinforcement cable layer and arranged on the
ground side, thus the reinforcement cable layer and the auxiliary
cable layer providing a two-layered structure. Also, the
reinforcement cable layer 21 and the auxiliary cable layer 22 may
be disposed to be aligned at suitable angles (within a range, in
which bending is not impeded) relative to a circumferential
direction of the body.
[0030] With the elastic-bodied crawler 10 structured in this
manner, the rollers 6, 6 press the inner peripheral surface 11a of
the body 11 on both sides of the driven projections 13, load
applied on the reinforcement cable layer 21 in positions
immediately below treads of the rollers 6, 6 is propagated to the
respective reinforcement cables 21a to be applied on the central
portion, on which load is not directly applied, by virtue of the
structure, in which the reinforcement cable layer 21 arranged on
the central portion in a widthwise direction of the body 11 and
oriented in a direction intersecting the circumferential direction
of the body is embedded in the body to lie below those surfaces,
which are pressed by the rollers 6, 6. As a result, the
reinforcement cable layer 21 arranged widthwise enhances rigidity
of the central portion in the widthwise direction of the body 11,
that is, the ground pressure distribution on the ground surface of
the lug portion 12 is equalized generally in the widthwise
direction.
[0031] Since the reinforcement cable layer 21 fulfilling such
function is arranged relative to the circumferential direction of
the body 11 formed from an elastic material, for example, in a
state, in which steel cables are oriented in the widthwise
direction and aligned in one layer, the crawler is not prevented
from bending and can be freely bent in the circumferential
direction. However, rigidity of the respective steel cables
(reinforcement cables 21a) fulfils the function of preventing
bending in the widthwise direction. As a result, load applied
through the rollers 6, 6 as described above is propagated to entire
lengths of the reinforcement cables 21a to be applied to the lug
portions 12 through that portion of the body 11, in which the
reinforcement cables 21a are embedded. In addition, the auxiliary
cable layer 22 arranged as a second layer on the ground side serves
to enhance rigidity there to assist in the propagation of load. In
addition, the length b of steel cables constituting the
reinforcement cable layer 21 will not develop the above function
even in the case of being too large, and will lose the function of
propagating load applied by the roller in the case of being too
small. Accordingly, a ratio (approximately 1/2 of the width B of
the body) shown in FIG. 2 is preferable in terms of economy or the
like.
[0032] FIG. 4 is a transverse, cross sectional view showing an
elastic-bodied crawler according to a second embodiment. The
elastic-bodied crawler 10A according to the second embodiment is
fundamentally the same in constitution as that according to the
first embodiment, but is different therefrom partly in the
structure of load propagating means embedded in the body 11.
Accordingly, except different portions of the load propagating
means, the same reference numerals denote the same elements as
those in the above embodiment, and a detailed explanation therefor
is omitted.
[0033] With the elastic-bodied crawler 10A according to the second
embodiment, reinforcement cable layers 23 as the load propagating
means 20A provided centrally in a widthwise direction and disposed
on a side of the reinforcement layer 15A of the main cables 15
embedded in the body 11 for the reinforcement purpose, toward the
ground surface are centrally divided into halves, which lie in
projected areas of root portions of the driven projections 13 to be
arranged on portions corresponding to portions of treads of the
rollers.
[0034] The reinforcement cable layers 23, 23 serving as the load
propagating means 20A in the embodiment are arranged in a
left-right symmetric manner in the widthwise direction in a state,
in which steel cables are used and oriented in a direction
intersecting a circumferential direction of the body in the same
manner as in the first embodiment and a multiplicity of
reinforcement cables are aligned circumferentially such that one
ends thereof are disposed in projected areas of root portions of
the driven projections 13 disposed centrally in the widthwise
direction and the other ends thereof lie in portions immediately
below treads of the rollers, and further reinforcement cable layers
23' are arranged and embedded to be offset in positions further
centrally than the reinforcement cable layers 23, thereby enhancing
rigidity in the central portion.
[0035] With the elastic-bodied crawler 10A structured in such
manner, the load propagating means 20A housed therein is
constructed to be divided centrally in the widthwise direction, but
the same function as that in the above embodiments can be fulfilled
because the reinforcement cable layers 23, 23' in two upper and
lower layers cause load applied by the rollers to be propagated
centrally from the reinforcement cable layers, which extend to
portions immediately below the treads. In addition, the
reinforcement cables in the present embodiment may be aligned at a
predetermined angle relative to a circumferential axis. In this
case, it is necessary to select an inclination of such magnitude
that bending in a circumferential direction is not impeded. In this
manner, although the reinforcement cable layers 23 (23' ) are
constructed to be divided centrally, there is given an effect that
the central portion of the body 11 is further enhanced.
[0036] FIG. 5(a) is a transverse cross sectional view showing an
elastic-bodied crawler according to a third embodiment, and FIG.
6(b) is a longitudinal cross sectional view showing the
elastic-bodied crawler partially. An elastic-bodied crawler 10B
according to the third embodiment is fundamentally the same in
constitution as that in the first embodiment but is different
therefrom in the constitution of load propagating means 20B
embedded in the body 11. Accordingly, the same reference numerals
denote the same or similar elements as those in the above
embodiment except the load propagating means, and a detailed
explanation therefor is omitted.
[0037] With the elastic-bodied crawler 10B according to the third
embodiment, core bodies 25 are used as the load propagating means
20B provided in the body 11. In this load propagating means 20B,
the core bodies 25 are arranged circumferentially of the body 11 on
a side of a layer 15A of main cables 15 toward the ground in a
pitch 1/n (n: integer) times a pitch P of the driven projections 13
in the same manner as the embodiment with the reinforcement cable
layer 21 housed therein, the core bodies having a length b bridging
projected areas of root portions of the driven projections 13
centrally of the body 11 in a widthwise direction and extending on
both side of the projected areas, and a width L at least smaller
than the pitch P of the driven projections 13. In addition, that
pitch, in which the core bodies 25 are arranged, is 1/2P. A
thickness of the core bodies 25 can be set optionally in that
range, in which they can be embedded in the body 11, in accordance
with a material forming them.
[0038] Also, it is preferable that the core bodies 25 be formed
from a material having a higher Young's modulus than that of an
elastic material (rubber material), which forms the body 11 of the
crawler. Thus flexibility of the crawler at the time of running can
be maintained, and generation of local load in the ground surface
portion can be prevented by causing load pressure applied on the
treads by the rollers to be propagated generally to those portions,
in which the core bodies are embedded, by the core bodies 25 in the
same manner as in the above embodiment to enable uniformly
distributing the load not only in the areas immediately below the
treads of the rollers but also in the central portion in the
circumferential direction. In particular, plate-shaped pieces are
incorporated to be able to function as the load propagating means
20B more markedly.
[0039] In order to fulfill such function, it is preferable to use,
for example, high-hardness rubber, urethane resin, plastics (for
example, phenol resin reinforced by a reinforcement material)
having a high mechanical strength, or metal such as aluminum, iron
or the like for the core bodies 25. In addition, organic materials
among the above materials have an advantage that uniform resin
molding scan be used. Also, inorganic materials can be made thin to
attain the object. In addition, that pitch, at which the core
bodies 25 are arranged, is made 1/2P relative to the pitch P of the
driven projections 13, whereby the function of equalizing a load
distribution on the ground surface portions, the load being applied
by the rollers, can be fulfilled without impeding bending of the
body 11 in the circumferential direction.
[0040] In the constitution, in which the core bodies 25 are used as
the load propagating means 20B, the core bodies 25 are formed
centrally on one surface (surface toward the driven projections)
thereof with a projection 26 as shown in FIG. 6(a), whereby such
projection can be used in determining positions, in which the core
bodies 25 are embedded, at the time of forming of the crawler.
Also, as shown in FIG. 6(b), core bodies 25a, 25a as divided are
arranged and embedded centrally in the widthwise direction of the
body 11 to extend from projected areas of root portions of the
driven projections 13 to both sides thereof, whereby load applied
on positions immediately below the treads of the rollers are
propagated to the central portion to enable equalizing the ground
pressure distribution.
[0041] As described above, the elastic-bodied crawler according to
the invention has advantages that the load propagating means is
arranged in the body centrally in the widthwise direction of the
body 11 to enable equalizing the ground pressure distribution, and
members incorporated as the load propagating means are embedded in
a state, in which they are easy to separate in the circumferential
direction, whereby at the time of disposal after use the members of
the load propagating means being constructed to be
circumferentially discontinuous can be simply cut for easy disposal
when the main cables can be cut.
* * * * *